1882. ] MOLLUSCAN FAUNA OF MADAGASCAR. 387 
strongly lirated for this genus. It is a smaller form than P. mada- 
gascariensis, has a shorter and more obtuse spire, a narrower per- 
foration and spiral striation. P. lirata is more strongly lirate than 
it, has the spire even still shorter, the body-whorl is prominently 
shouldered above, and the aperture is longer in proportion. 
PLANORBIS MADAGASCARIENSIS, sp. nov. (Plate XXII. figs. 
20-22.) 
Shell moderately thick, deeply excavated both above and below, 
corneous brown, rather strongly striated by the lines of growth, 
and sometimes exhibiting traces of spiral striation. Whorls 4—43, 
rapidly increasing; the last large, rather high, convex, rather deeply 
incurved at the suture both on the upper and underside, finely 
malleated, chiefly round the middle. Aperture largish, broadly 
lunate, raised above or on a level with the penultimate whorl. 
Peristome thin, receding at the base, its extremities connected by a 
very thin deposit of callus on the whorl. 
Greatest diam. 123 millim., smallest 10, height 43. 
Hab. Lake Itasy (Johnson). 
This species is very like P. pfeifferi, Krauss (Sudafr. Moll. pl. v. 
f. 7), but may be distinguished by the malleation of the last whorl, 
its greater height, and browner colour. 
NeERITINA GAGATES, Lamarck. 
Neritina gagates, Lamarck (vide Martens, Conch. Cab. p. 94). 
Hab. Tamatave (Cowan). 
Two specimens from the above locality I believe to belong to this 
species, differing only in the deep red colour of the columellar 
callosity, and the olive-green tint of the outer lip. The form is the 
same; and the denticles on the columella, the painting, the micro- 
scopic spiral sculpture, and the operculum are all similar. 
NERITINA FULGETRUM, Reeve. (Plate XXII. figs. 23, 24.) 
Neritina fulgetrum, Reeve, Conch. Icon, pl. 23. f. 103 a, sp. 103. 
Hab. ? (Reeve) ; south of Tamatave (Johnson). 
This species has hitherto been represented by a single specimen 
without any locality in the Cumingian collection, now in the British 
Museum. As the description in the ‘Conchologia Iconica’ is very 
short and incomplete, I will here add a few further details. The 
black zigzag lineolation at times is very close, thus giving the shell 
a greyish appearance when viewed at a distance ; anda character not 
referred to by Reeve, but indicated in his figure, is the brown margin 
to the body-whorl at the suture, beneath which the volution is faintly 
constricted. The columellar callosity is much thickened and of a red 
colour, and extends some distance over the whorl. The edge of the 
columella is pale, straight, with a shallow sinus a little below the 
middle, furnished with about a dozen denticles. The aperture is 
rather small, bright yellow far within, then whitish, and again yellow 
or greenish-yellow at the lip. The operculum is slaty black ex- 
